Vehicles operating within underground environments produce large volumes of data from a diversity of sensors and systems including engine and transmission parameters, emissions, weights, pre operations checklist, production statistics, ground speed, location, tire conditions, and alarms. Retrieving this data set and transferring it to the surface or to any other facility monitoring the underground environment is a key factor for monitoring and improving the utilization of the vehicles both from a safety perspective and an efficiency perspective.
Underground environments, such as mines, transportation and service tunnels to mention a few, usually have limited wireless network connectivity, with wireless access points sparsely distributed around the underground environment. A vehicle may enter a hotspot (area with Wi-Fi coverage on an underground location) during its work cycle. Sometimes the vehicles are only exposed to seconds of network connectivity per day. A store-and-forward system which is configured to transmit prioritized data is required to effectively monitor the vehicle(s)/underground environment conditions.
There is a great diversity of technologies available for underground communication, including but not limited to, Wi-Fi, Leaky Feeder, through-the-earth (TTE), digital radio, mesh networks and others. Each technology has its different bandwidth capacities and different availabilities in the underground environment. For example, an underground environment could have a Wi-Fi network offering high-bandwidth data transfer but vehicles are typically only in range giving transmission coverage for several seconds during their cycle, also a Leaky Feeder network could be available offering extended coverage time but at lower bandwidth. It is common that underground infrastructure includes a mixture of these technologies.